Process for the treatment of woolen materials and blends thereof

ABSTRACT

An applicative and preparative process for the disposition of woollen and wool blend materials intended for articles to be printed, dyed or bleached, for conferring on said wool and wool blends improved shrinkage resistance and non-felting characteristics which consists of treating the material initially and successively with an initial single primary disproportionation reaction and/or advantageously with an alternate disproportionation reaction.

United States Patent 1191 Verri et al. 1 Oct. 2, 1973 I5 PROCESS FOR THE TREATMENT OF 2,297,701 10/1942 Hug 8/128 R WOOLEN MATERALS AND BLENDS 2,130,570 9/l938 Volz 26/l9 THEREOF FOREIGN PATENTS OR APPLICATIONS [76] Inventors; Guido Verri; Anna Maria Verri, nee l,097,976 1/1968 Great Britain 8/l28 R Cesini, both f v n primule 4 579,584 8/1946 Great Britain 1. 8/128 R Milan, Italy Primary Examiner-Roland E. Martin, Jr. [22] led: June 1971 Attorney-Guido Modiano et al. [21] Appl. No.: 157,674

[57] ABSTRACT 52 US. (:1 8/128 R, 8/l27.5l, 8/1276 applicative and Preparative process for the disposi- [51] ML CL 006m 3/06, D06m 3/10, D061 13/36 tion of woollen and wool blend materials intended for [58] Field of Search 8/12751, l27.6, articles be Primed, dyed or bleached for conferring 8/128 R on said wool and wool blends improved shrinkage resistance and non-felting characteristics which consists of [56] Reerences Cited treating the material initially and successively with an UNITED STATES PATENTS initial single primary disproportionation reaction and- /or advantageously with an alternate disproportion- 2,l44,824 1/1939 Wiegand 8/l27.6 X ado reaction 2,732,277 1/1956 Gleissner et al. 8/l27.6 X 3,098,693 7/1963 Sheehan 8/128 R 7 Claims, No Drawings PROCESS FOR THE TREATMENT OF WOOLEN MATERIALS AND BLENDS THEREOF BACKGROUND OF THE INVENTION This invention relates to a process for the treatment of woollen and wool blend materials. In particular this invention relates to a process for conferring improved characteristics with regard to the disposition of woollen or wool blend materials intended for articles to be printed, dyed or bleached, and for conferring improved characteristics, in particular those of shrink resistance and nonfelting, on the pure or blended wool, i.e. containing percentages of cotton or other vegetable, artificial or synthetic fibers, either in the form of tops, yarn skeins or crossed reels, or in the form of an article previously formed from raw material.

l-leretofore separate processes had to be used in order to confer all the aforementioned characteristics, i.e. one process to obtain the disposition of the articles for printing, dyeing or bleaching, and another separate non simultaneous process for attaining of positive values of shrink resistance and non-felting in connection with various other processing stages. For the purpose a first type of process is conventionally used based essentially on the concept of a previous independent operation of chlorination or halogenation etc., which is completely separate, i.e. independent of a normal application treatment. An example of such type of process would be a more or less prolonged bleach and a possible after-dye of light or bright tints. These latter processing operations are not sufficient in themselves to obtain the simultaneous conferring of shrink resistant and nonfelting characteristics together with good conservation of the material.

The processes of conventional technology, although widely diffused, present in addition certain disadvantages, such as for example considerable loss of time in the case of chlorination treatment, etc., preliminary to bleaching in the case of the disposition of articles to be printed, and preliminary or successive in the case of pastel tints and the bleaching of wool of wool blends during the various processing stages. These are antieconomical factors both form the point of view of the time employed and the considerable consumption of often drinkable water, coupled with the consumption of chemical reagents which are not always of low cost.

SUMMARY OF THE INVENTION An object of the invention is to avoid the abovementioned disadyantages.

It has now been found that the aforementioned improved characteristics can be conferred simultaneously, i.e. for example directly during the applicative processes of bleaching and/or dyeing. It is evident that the conferring of said characteristics for the disposition of woollen and wool blend articles intended for printing, dyeing or bleaching, together with the simultaneous attainment of shrink resistant properties, or just the conferring of these latter properties on wool and wool blends (during the various processing stages as heretofor described) is particularly useful in those cases where the woollen or wool blend article is afterwards subjected to a number of washes for various reasons.

It is therefore the main object of the present invention to make available a process for the treatment of woollen articles for printing, dyeing or bleaching, and

to confer on the wool itself or to blends thereof improved characteristics during its various processing stages for the disposition of the material to printing, dyeing or bleaching, together with the obtainment or improvement of shrink resistant and nonfelting properties, which avoids the aforementioned disadvantages of previous technology, i.e. which is a single process, one which is not preliminary but which is directly carried out in the same applicative bleach baths for articles to be printed, dyed or bleached, and which is, at the same time capable of conferring shrink resistant and nonfelting properties to the wool or blends of it during the various processing stages. Another object is the utilization of compounds which are economically available commercially or economically obtainable and of reliable action which does not oppose the effects required to be attained and such as to guarantee the obtaining of adjustable values of brightness, purity of nuances and shrink resistance for the said woollen and wool blend products. The only exceptions are those cases relative to medium and dark flowing nuances for which a single application bath is not contemplated.

According to the invention the aforementioned objects are all attained by an applicative and preparative process for the disposition of woollen and wool blend materials intended for articles to be printed, dyed or bleached, for conferring on said wool and wool blends improved shrinkage resistance and non-felting characteristics, characterized in that it comprises treating the material with at least one disproportionation reaction.

Advantageously the starting material is treated initially and successively with a single primary disproportionation reaction and an alternate disproportionation reaction.

In this context the term primary single disproportionation reaction signifies a chemical reaction which is initially oxidizing and then reducing in the same application bath.

Advantageously this primary single disproportionation reaction is effected according to one characteristic of this invention by means of a bleach bath consisting of an aqueous solution having an initial pH value between 8.7 and 8, comprising at least one soaking compound of fatty alcohol esters and sodium alginate at low/medium viscosity, or for the disposition of articles to be printed a soaking compound (to be added to the material purge bath) comprising a non-ionogene fatty amine derivative; an alkali salt of pyrophosphoric acid, 20-30 percent by weight of the starting material of inorganic peroxide or 10-20 percent by weight of the starting material of organic peroxide, 2-3 percent by weight of a fundamental catalyst for the primary dismutation reaction such as dicyandiamide, possibly strengthened (especially if dealing with processings relative to tops which have very high felting values), a second activator or promotor catalyst, i.e. traces of 0.100 0.200 percent of a hydride which does not decompose violently in aqueous solution, such as a hydride of a metal or of an alkali metal with a metalloid, e.g. sodium boron hydride.

In this context the term alternate disproportionation reaction" signifies a chemical reaction which is initially reducing, followed by oxidizing tendencies. This reaction is usually subsequent to the primary disproportionation reaction.

Advantageously according to another characteristic of this invention, said alternate disproportionation reaction is effected with a bath consisting of an aqueous solution having a pH between 7.5 and 5.5 and comprising at least one alkali salt or alkali organic compound of sulfoxylic, hydrosufurous or pyrosphosphoric acid, and a catalyst for the disproportionation reaction such as sodium bisulfite monosodic.

DESCRIPTTON OF THE PREFERRED EMBODIMENTS Further characteristics will be more evident from the detailed description of some embodiments of the invention given by way of example. The given percentages and parts are by weight with respect to the weight of the material to be treated, if not otherwise indicated. The percentage shrinkage values by felting in area generally refer to the first 30 minutes of wash on the basis of international tests.

EXAMPLE 1 Conferring of adjustable values of shrink resistance and non-felting to tops.

About 1,000 lltg of pure wool in the form of tops and with a declared initial value of 42 percent shrinkage of area by felting were introduced into a stainless steel apparatus provided with a device for the circulation of the bath. Into this apparatus were loaded at room temperature, the quantities of water necessary (10,000 liters) comprising the following components, calculated as a percentage by weight of the weight of wool loaded, and added in the following precise order:

1. Primary single disproportionation reaction Oxidizing Reducing (Circulating bath with material still: material to water ratio, 1:10 approx.)

a. 0.300 0.500 percent fatty alcohol ester or 0.100 percent of sodium alginate at low/medium viscosity.

b. 0.100 0.200 percent sodium boro hydride as dismutation activator catalyst.

c. 2 3 percent fundamental dismutation catalyst in the form of a substance conventionally known by the name of raw dicyandiamide, titre about 99 percent.

(:1. 4 6 percent tetrasodium pyrophosphate, tetrasodic.

e. percent of a strength 130 volume water solution of hydrogen peroxide.

The aqueous solution, which after the addition of all reagents showed a pll-il value of 8.7 which was decreasing and consequently initially oxidizing, hydrolized after 2-3 hours to a pH value of 7.5, still decreasing. The temperature of the disproportionation bath was in the meantime gradually brought over a period of threefourths hour (by heating with indirect steam) to the optimum temperature of 50 C., this temperature being maintained by a thermostat for about 6 hours (the bath circulation stopped however after l-2 hours from the start). The bath was then allowed to cool overnight to a final temperature of 40 C.

Subsequently, after 2-3 hours, the actual disproportionation began, i.e. the initially oxidizing chemical action transmuted gradually into a reducing action, and precisely during this second chemical reaction the values of shrink resistance and non-felting begin to be conferred on the material treated, and to be accentuated.

As the oxidation-reduction treatment in order to come to proper completion has to last a minimum of 8 hours in this case, it may well be prolonged up to a full 48 hours, and in fact, in such a long period of time the required characteristics, the object of the invention, are accentuated. On termination of the aforementioned treatment the material was rinsed in a cold water bath, after which it was acidified, the old rinse bath being discarded, in a new circulating bath at a temperature of 30-40 C. containing a quantity varying between 0.5 percent and 1 percent of percent acetic acid, after which the application is proceeded with. At this point the material thus treated and dried shows a shrinkage in area by felting varying from 18 to 26 percent, these percentages being more than sufficient for proceeding further, namely:

2. Alternate disproportionation reaction: Reducing- Oxidizing The material from the first disproportionation reac tion as heretofor described and still wet was treated in a new bath consisting of an aqueous solution comprising a compound previously mixed in a mixer suitable for mixing powders and which, in terms of percentage by weight of initial material to be treated, consists of:

a. 5 percent sodium hydrosulfite titred at about percent, possibly stabilized with buffer agents such as Na P O sodium sulphite, etc., all of which lie within the field of the inventive concept, and evident to a technician in this field.

b. 2.5 percent sodium formaldehyde sulfoxylate, titre about 96-98 percent.

0. 1.2 percent disodium dihydrogen pyrophosphate.

d. 0.9 percent monosodic sodium bisulfite as catalyst for favoring afterwards the disproportion reaction in the second bleach or dye bath, i.e. reducing with oxidizing tendency. lf required an opportune quantity of optical bleach suitable and resistant to said reagents can be added integrated, in the case of certain applications, with traces of vat dyes or leucoesters.

The whole, i.e. the above preparation, was dissolved in the aforementioned bath bringing the temperature of said bath to 65-75 C within three-fourths hour. After this the bath was left to cool, the indirect steam being shut off. In 1 or 2 hours the application was complete. During the first minutes of operation there was a prevalent reducing chemical reaction, then after this period of time the actual dismutation reaction began, i.e. an ever increasing tendency towards an oxidizing reaction of the treatment bath was verified, by means of which the material assumes a better feel to the hand.

Then the treated material was rinsed in a fresh bath of cold water, if necessary acidifying in a fresh bath of material with 1 percent of acetic formic acid, after which it is rinsed and dried. llf after this treatment pure and bright nuances with normal neutral or acid dyes are to be obtained, an after-dye with said dyes is proceeded with.

If however general exceptional fastness is to be obtained for the desired pastel tints, dyeing can be carried out directly with suitable vat dyes or leucoesters directly in the reducing-oxidizing disproportionation bath. These categories of dye are pseudo-solubilized or solubilized separately in the necessary quantity of hot water and then added to the bath with caution, with the material absent. Then the bath with this addition is pumped in to the apparatus containing the material which is dyed normally as in the case of common neutral colors for wool. The leucoreduction of vat dyes or the leuco fixing of the leucoester dyes takes place spontaneously in the dye bath when the temperature reaches 70 C, and is improved if a reducing catalyst is present such as 1 2 percent of 22 Be ammonium hydrate or 0.500 percent of approximately 95 percent titre anhydrous piperazine. The complete fixing of the dye is obtained at a temperature of 80 85 C. After l-2 hours of treatment dyeing can be considered complete. The development of the tints obtained with vat dyes is produced by discarding the old dye bath and oxidizing the material in a new separately formed bath at a temperature of 40 50 C containing 3 6 percent of a 130 volume strength water solution of hydrogen peroxide after which it is rinsed in a new bath containing 0.5 percent of 80 percent acetic acid, if necessary rinsing further with cold water and drying.

For leucoester dyes, as oxidation of the dyes is more difficult a successive aeration treatment is opportune.

With reference to example I following said observations, it should be noted that, while the preceding values of percentage area shrinkage by felting, were already revalued at 18 26 percent after the first disproportionation reaction, whether the natural white is extended (in the absence of optical bleaches), or whether blued (in the presence of optical bleaches), or whether an after-dye with acid dyes for contemporary dyeing is rendered necessary, the aforementioned area shrinkages by felting descend in the second alternate dismutation process with vat dyes or leucoesters to percentages between 4 and 5 percent if an addition of 0.100 0.200 percent by weight of sodium boro hydride was made during the first primary single disproportionation process. Said percentage area shrinkages by felting are only reduced to 12 l6 18 percent for woollen tops if the addition of sodium boro hydride as activator or promoter catalyst is omitted. All these percentages are useful and sufficient, compatible with the subsequent processing of the woollen tops, since, after the wool has been spun into the various counts of yarn these various area shrinkage percentages by felting will automatically descend to values of 0.0 3.5 percent measured according to international shrink resistant tests (precisely because they are now part of the physical state of yarn).

EXAMPLE 2 Conferring of absolute shrink resistant and nonfelting values to woollen and wool blend material in the form of yarn skeins. (Bath ratio of material to water, not more than 1:20 1:25). 50 Kg of woollen yarn in skeins of count 2/32 with an initial declared value of 21 percent of area shrinkage by felting were introduced into a stainless steel apparatus with a device for circulating the bath. Into this apparatus the necessary quantity of water at room temperature containing all the components as already described in Example 1 relative to woollen tops was introduced, but ommitting the addition of sodium boro hydride traces provided that the same application is to be completed followed by alternate disproportionation.

After said first disproportionation reaction, i.e. oxidizing reducing, area shrinkage values by felting of 5 6 percent were obtained in the absence of sodium boro hydride traces, whereas these values were 2.5 3.5 percent in the presence of traces of sodium boro hydride. After the second process of alternate disproportionation the said initial declared values descend to 0.0 1 percent of area shrinkage by felting. The other operations, i.e. natural white or blueing, dyeing with fast acid dyes, vat dyes, or leucoesters do not undergo any modifications from the foregoing observations as regards shrinkage resistant effects, except in this case the possibility, where an addition of traces of sodium boro hydride has been made, of being able to dye directly with neutral or acid dyes immediately after disproportionation, omitting (contrary to woollen tops) the alternate disproportionation process.

EXAMPLE 3 Conferring of specific characteristics such as immediate hydrophilia and affinity for the application of printing pastes, improvements in the values of area shrink resistance by felting or the specific conferring of shrink resistance and non-felting characteristics to wool or wool blends in the form of pieces or bolts to be or not to be subjected to disposition for printing.

In this specific case in some instances the material already initially presents positive shrinkage resistance values because of its particular physical state. Nevertheless the procedure hereinafter described improves these values or confers them on that material which is particularly felting in its initial state. Such a material shows an area shrinkage percentage by felting, in its raw state, of 17.4 percent (after 30 minutes wash) and 27.9 percent (after 60 minutes wash). After the treatment hereinafter described the said values descend to 0.0 or 0.3 percent (after 60 minutes wash). (Ratio of material to water in bath, 1:25 approximately) 10 Kgs of pure wool in piece or bolt form were introduced into a stainless steel apparatus provided with a device for circulating the bath or the material (stirrer), and closed with a glass or plastic cover. The necessary quantity of water at ambient temperature was fed into this apparatus. A quantity variable according to the compactness of the material from 1 to 2 percent of non-ionic fatty amine derivative was added to the bath. The bath was heated to a temperature of 90 C and agitated for a period of about three-fourths hour, then the material was rinsed with running cold water which flew to drain. It was than again completely rinsed and the treatment proceeded in a new bath as already described under Example 2, with the difference that the temperature of the initial single disproportionation process was increased to 60 C, while in the second alternate disproportionation process in addition to the already stated reagents a quantity of 0.5 percent, by weight of the material, ofa soaking agent in the form of a non-ionic fatty acid derivative was added, and the temperature of the bath was maintained at C for one-half to 1 hour. None of the remaining process details change, including the stated exceptions. The values of percentage area shrinkage by felting were positive, i.e. improved with respect to the initial values, and the material thus treated was perfectly hydrophile so as to rapidly absorb the printing paste where it was thought useful to carry out the printing operation, or perfectly suitable for a possible superior after-dye with any type of dye, or could already be considered finished with regard to natural white or blued requirements.

Referring now to Example 3 following said observations, it should be noted that when material is to be treated which for various reasons already possesses positive shrinkage resistance values, whatever its physical state it is advisable to effect the following operation thus redimensioned from the applicative aspect.

After having purged the material in the apparatus as already described, it is treated directly or simply in a new bath (ratio of material to water 1:20 approximately) containing:

a. 2 3 percent disodium dihydrogen pyrophosphate b. 2 3 percent of approximately 99 percent raw dicyandiamide.

While the material is circulating or vice versa, the bath is gradually heated over three-fourths hour to 70 C and circulation continues at this temperature for about three-fourths hour.

The material is then rinsed and possibly treated in a new bath as already described in Example 1 relative to woollen tops, omitting the primary disproportionation and passing directly to the alternate disproportionation, reducing oxidizing. After this the procedure is as heretofor described.

The invention so conceived is susceptible to numerous variations and modifications all of which enter within the field of the inventive concept.

Thus for example while the products necessary for the application of the second alternate disproportionation reaction are described under the preparatory aspect, the necessary products in addition to being singularly dissolved and added to the applicative baths can be much more economically mixed together separately in batch or continuous mixers (for quickly obtaining large quantities of finished product) and the whole of the preparation be then added to the application bath in quantities referred to the total of the mixture. Moreover the sodium boro hydride may be added to the bath as heretofor stated, as a complementary product to the dicyandiamide, and the addition is indicated and specified as the second product for the said bath at a temperature not initially greater than ambient temperature. Advantageously this sodium boro hydride must not exceed 0.1 0.2 percent by weight of the material to be treated, because for higher quantities the chemical reaction could be too violent and the major part of the bath could overflow from the application apparatus. In the case of application of the process to articles in pieces to be treated for conferring shrinkage resistance or improved shrinkage resistance together with a disposition for printing, an initial purge phase for the material to be treated is scheduled. The purge bath must be heated to 90 C and up to 2 percent by weight of a noniogene fatty amine derivative added to it. This latter must also be added to the second alternate dismutation bath but in the quantity of 0.5 percent by weight.

lln practice the substances used and the quantities of said substances and materials used, and the temperatures of the treatment baths can be varied within limits which are slightly different to those cited in the examples, in accordance with the requirements of application, remembering that in said examples a water was used in the treatment chambers which had a hardness of up to German degrees. The duration and speed of the circulation application baths must always be adjusted compatible with the delicacy and physical aspect of the material to be treated, and which would be immediately evident to a technician of this field.

It will be understood that the scope of this invention extends its protective field also over all those compositions destined for carrying out the process as claimed hereinafter.

We claim:

Il. In a process for reducing the felting and shrinking properties of a woollen material, and contemporaneously bleaching the woollen material and increasing its dye-receptivity, which process comprises contacting the woollen material with a first aqueous alkaline bath containing a peroxy compound and thereafter contacting the woollen material with a second aqueous bath comprising a sulphur-containing reducing agent, the improvement wherein:

a. said first bath comprises from 4 to 6 percent by weight based on the woollen material, of tetrasodium pyrophosphate;

from 2 to 3 percent by weight based on the woollen material, of dicyandiamide;

from 0.1 to 0.2 percent by weight based on the woollen material, of sodium borohydride;

from 0.3 to 0.5 percent by weight based on the woollen material, of a soaking compound selected from the group consisting of fatty alcohol esters;

from 20 to 30 percent by weight based on the woollen material, of a volume strength water solution of hydrogen peroxide, or from 10 to 20 percent by weight based on the woollen material, of a water-soluble organic peroxide; and

b. said second bath comprises:

4.25 percent by weight based on the woollen material, of sodium hydrosulfite;

2.5 percent by weight based on the woollen material, of sodium formaldehydesulfoxylate 1.2 percent by weight based on the woollen material, of disodium dihydrogen pyrophosphate;

0.9 percent by weight based on the woollen material, of sodium bisulfite.

2. The process of claim l1, wherein the first bath has an initial pH value comprised between 8.7 and 8.5, and the second bath has an initial pH value comprised between 7.5 and 5.5.

3. The process of claim 11, wherein the weight ratio of the woollen material to each bath is comprised between l:l0 and 1:25.

t. The process of claim 3, wherein said woollen mate rial is selected from the group consisting of tops and woven fabrics, and said weight ratio is comprised between 1:10 and 1:12.

5. The process of claim 3, wherein said woollen material consists of skeins and said weight ratio is comprised between 1:15 and 1:25.

6. The process of claim ll, wherein the second bath further comprises a coloring substance selected from the group consisting indigoid and anthraquinone types of vat colors and leucoesters.

7. The process of claim 6, wherein the second bath further comprises 0.5 percent by weight based on the woollen material of anhydrous piperazine. 

2. The process of claim 1, wherein the first bath has an initial pH value comprised between 8.7 and 8.5, and the second bath has an initial pH value comprised between 7.5 and 5.5.
 3. The process of claim 1, wherein the weight ratio of the woollen material to each bath is comprised between 1:10 and 1:25.
 4. The process of claim 3, wherein said woollen material is selected from the group consisting of tops and woven fabrics, and said weight ratio is comprised between 1:10 and 1:12.
 5. The process of claim 3, wherein said woollen material consists of skeins and said weight ratio is comprised between 1: 15 and 1:25.
 6. The process of claim 1, whErein the second bath further comprises a coloring substance selected from the group consisting indigoid and anthraquinone types of vat colors and leucoesters.
 7. The process of claim 6, wherein the second bath further comprises 0.5 percent by weight based on the woollen material of anhydrous piperazine. 